87228-44-2Relevant academic research and scientific papers
Macrolactonization Reactions Driven by a Pentafluorobenzoyl Group**
Ciofini, Ilaria,Force, Guillaume,Leb?uf, David,Mayer, Robert J.,Perfetto, Anna
supporting information, p. 19843 - 19851 (2021/08/13)
Macrolactones constitute a privileged class of natural and synthetic products with a broad range of applications in the fine chemicals and pharmaceutical industry. Despite all the progress made towards their synthesis, notably from seco-acids, a macrolactonization promoter system that is effective, selective, flexible, readily available, and, insofar as possible, compatible with manifold functional groups is still lacking. Herein, we describe a strategy that relies on the formation of a mixed anhydride incorporating a pentafluorophenyl group which, due to its high electronic activation enables a convenient access to macrolactones, macrodiolides and esters with a broad versatility. Kinetic studies and DFT computations were performed to rationalize the reactivity of the pentafluorophenyl group in macrolactonization reactions.
Tropolonate salts as acyl-transfer catalysts under thermal and photochemical conditions: Reaction scope and mechanistic insights
Mai, Binh Khanh,Koenigs, Rene M.,Nguyen, Thanh Vinh,Lyons, Demelza J.M.,Empel, Claire,Pace, Domenic P.,Dinh, An H.
, p. 12596 - 12606 (2020/11/18)
Acyl-transfer catalysis is a frequently used tool to promote the formation of carboxylic acid derivatives, which are important synthetic precursors and target compounds in organic synthesis. However, there have been only a few structural motifs known to efficiently catalyze the acyl-transfer reaction. Herein, we introduce a different acyl-transfer catalytic paradigm based on the tropolone framework. We show that tropolonate salts, due to their strong nucleophilicity and photochemical activity, can promote the coupling reaction between alcohols and carboxylic acid anhydrides or chlorides to give products under thermal or blue light photochemical conditions. Kinetic studies and density functional theory calculations suggest interesting mechanistic insights for reactions promoted by this acyl-transfer catalytic system.
2,6-Dimethyl-4-nitrobenzoic anhydride (DMNBA): An effective coupling reagent for the synthesis of carboxylic esters and lactones
Shiina, Isamu,Miyao, Ryo
experimental part, p. 1313 - 1328 (2009/07/05)
Various carboxylic esters are obtained at room temperature in excellent yields with high chemoselectivities from nearly equimolar amounts of carboxylic acids and alcohols using 2,6-dimethyl-4-nitrobenzoic anhydride with triethylamine by the promotion of 4-(dimethylamino)pyridine. The efficiency of the esterification is compared to those of other dehydrations using substituted benzoic anhydrides as coupling reagents. This method was successfully applied to the synthesis of threo-aleuritic acid lactone and the desired 17-membered ring compound was prepared in high yield at room temperature from the corresponding free trihydroxycarboxylic acid using 2,6-dimethyl-4-nitrobenzoic anhydride in the presence of 4-(dimethylamino)pyridine.
A mild and efficient chemoselective protection of primary alcohols as pivaloyl esters using La(NO3)3·6H2O as a catalyst under solvent-free conditions
Prabhakar,Suryakiran,Venkateswarlu
, p. 732 - 733 (2008/02/09)
Primary alcohols are selectively and efficiently protected as their pivaloyl esters with pivaloyl chloride in the presence of catalytic amounts of La(NO3)3·6H2O at room temperature under solvent-free conditions in excellent yields. Copyright
Widely useful DMAP-catalyzed esterification under auxiliary base- and solvent-free conditions
Sakakura, Akira,Kawajiri, Kimio,Ohkubo, Takuro,Kosugi, Yuji,Ishihara, Kazuaki
, p. 14775 - 14779 (2008/09/17)
With regard to atom economy and E-factor, catalytic condensation of carboxylic acids with equimolar amounts of alcohols is the most desirable. Although several highly active dehydration catalysts have been reported, more efficient alternatives are still strongly needed because the dehydrative esterification of tertiary alcohols, phenols, acid-sensitive alcohols, amino acids, and hardly soluble alcohols has never proceeded satisfactorily. Here we report new insights into the classical DMAP-catalyzed acylation of alcohols: surprisingly, only a 0.05-2 mol % of DMAP can efficiently promote acylation of alcohols with acid anhydrides under auxiliary base- and solvent-free conditions to give the corresponding esters in high yields. Furthermore, we achieved the recovery and reuse of commercially available polystyrene-supported DMAP without using any solvents. These serendipitous findings provide widely useful and environmentally benign esterification methods, which might be more practical and reliable than catalytic dehydrative condensation methods, in particular, for the less reactive alcohols which hardly condense with carboxylic acid directly.
Simple method for the preparation of esters from Grignard reagents and alkyl 1-imidazolecarboxylates
Werner, Thomas,Barrett, Anthony G. M.
, p. 4302 - 4304 (2007/10/03)
The reaction of Grignard reagents with alkyl imidazolecarboxylates, which were prepared from alcohols with carbonyl diimidazole, gave the corresponding esters in good to excellent yields. This method conveniently provides esters from alkyl halides and alcohols by C1-carbon chain extension.
Efficient method for the esterification of carboxylic acids with alcohols using di-2-thienyl carbonate promoted by catalytic amounts of DMAP and Hf(OTf)4
Oohashi, Yoshiaki,Fukumoto, Kentarou,Mukaiyama, Teruaki
, p. 190 - 191 (2007/10/03)
Esterification of carboxylic acids with alcohols including bulky secondary ones by using an equimolar amount of di-2-thienyl carbonate (2-DTC) in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP) followed by addition of a catalytic amount of hafnium(IV) trifluoromethanesulfonate (Hf(OTf)4) afforded the corresponding esters in good to high yields. Copyright
A new method for the synthesis of carboxylic esters and lactones with di-2-thienyl carbonate (2-DTC) by the promotion of DMAP and iodine
Oohashi, Yoshiaki,Fukumoto, Kentarou,Mukaiyama, Teruaki
, p. 1508 - 1519 (2007/10/03)
The esterification of carboxylic acids with alcohols by using di-2-thienyl carbonate (2-DTC) in the presence of a catalytic amount of 4-(dimethylamino) pyridine (DMAP) proceeded smoothly to afford the corresponding esters in good-to-high yields along with 2(5H)-thiophenone. This esterification was accelerated by the addition of an equimolar amount of iodine to afford the esters in higher yields within a shorter reaction time. Further, cyclization of ω-hydroxycarboxylic acids with an equimolar amount of 2-DTC in the presence of a catalytic amount of DMAP, followed by the addition of 1-4 equimolar amounts of iodine, afforded the corresponding lactones in good-to-high yields under mild conditions. This method was successfully employed in the synthesis of erythro-aleuritic acid lactone.
An effective method for the synthesis of carboxylic esters and lactones using substituted benzoic anhydrides with Lewis acid catalysts
Shiina, Isamu
, p. 1587 - 1599 (2007/10/03)
An efficient mixed-anhydride method for the synthesis of carboxylic esters and lactones using benzoic anhydride having electron withdrawing substituent(s) is developed by the promotion of Lewis acid catalysts. In the presence of a catalytic amount of TiCl2(ClO4)2, various carboxylic esters are prepared in high yields through the formation of the corresponding mixed-anhydrides from 3,5-bis(trifluoromethyl)benzoic anhydride and carboxylic acids. The combined catalyst consisting of TiCl 2(ClO4)2 together with chlorotrimethylsilane functions as an effective catalyst for the synthesis of carboxylic esters from free carboxylic acids and alcohols with 4-(trifluoromethyl)benzoic anhydride. Various macrolactones are prepared from the free ω-hydroxycarboxylic acids by the combined use of 4-(trifluoromethyl)benzoic anhydride and titanium(IV) catalysts together with chlorotrimethylsilane under mild reaction conditions. The lactonization of trimethylsilyl ω-(trimethylsiloxy) carboxylates using 4-(trifluoromethyl)benzoic anhydride is also promoted at room temperature in the presence of a catalytic amount of TiCl 2(ClO4)2. An 8-membered ring lactone, a synthetic intermediate of cephalosporolide D, is successfully synthesized according to this mixed-anhydride method using 4-(trifluoromethyl)benzoic anhydride by the promotion of a catalytic amount of Hf(OTf)4.
Efficient method for the esterification of carboxylic acids with alcohols using di-2-thienyl carbonate promoted by DMAP and iodine
Oohashi, Yoshiaki,Fukumoto, Kentarou,Mukaiyama, Teruaki
, p. 968 - 969 (2007/10/03)
Reaction of carboxylic acids with alcohols by using an equimolar amount of di-2-thienyl carbonate (2-DTC) in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP) followed by addition of an equimolar amount of iodine proceeded smoothly to afford the corresponding esters and 2(5H)-thiophenone in good to high yields.
